Adhering textile materials to rubber



United States Patent ()1 3,097,109 ADHERING TEXTILE MATERIALS T RUBBERArthur C. Danlelson, Royal Oak, Mlch., assiguor to United States RubberCompany, New York, N.Y., a corporation of New Jersey No Drawing. FiledJan. 15, 1962, Ser. No. 166,377 20 Claims. (Cl. 117-462) This inventionrelates to improvements in the method of adhering textile materials torubber, and to the improved laminates so obtained.

In certain rubber articles designed to withstand considerable stressesin 'use, the rubber is reinforced with plies of comparativelyinextensiblc textile materials. Rubber hose, belts and tires arecommonly reinforced with textile material in the form of fibers,including staple, yarns, cords, bats, or woven or braided fabric. Insuch articles, it is important that the plies of textile reinforcingmaterial be firmly adhered to the rubber intermediate the textile pliesand remain effectively adhered even after the article has been subjectedto repeated varying strains in use, because any separation and relativemovement of the rubber and textile parts leads to abrasion between theseparts and consequent early failure.

According to the present invention, there is provided an improved methodfor adhering textile material to rubber, for example in adhering theplies of tire cord fabric to the tire carcass stock.

In carrying out the present inventionyadhesion of the textile materialto the adjacent rubber is greatly improved by the use of a resinousreaction product of resoreinol and an N methylol carboxylic acid amide.Instead of the resoreinol component of the resinous reaction product,other meta disubstituted benzenes in which each of the substituerrts isan OH, NH; or OCOCH radical, e.g., maminophenol, m-phenylenediamine,resorcincl monoacetate, resoreinol diacetate, or 1,5-naphthalenediol, orpartially reacted resoreinol-formaldehyde resin, which materials areequivalent to the resoreinol, may be used. The rubber intermediate thetextile plies may be applied in the usual manner by calendering acoating of a vulcanizlable rubber composition on the textile material,generally on both sides, e.g. as in the conventional coating of tirecord fabric with tire carcass stock. The textile material, such as tirecord fabric, may optionally previously have applied thereto a thincoating of rubber by passing the ttxtile material through a bath of anaqueous dispersion of rubber, such as rubber latex, and drying. Thisso-called solutioning treatment is common practice. The two componentsof the resin, namely the resorcinol and N-methylolamide, are mixed alongwith conventionel compounding ingredients in the dry solid rubber to becalendered on the textile material. The rubber compound is thencalendered onto the bare or latex treated textile material. The amountof the resin components mixed with the rubber is not critical.Generally, 0.5 to 8 parts, and preferably 1 to 4 parts of the tworesin-forming components (total) per 100 parts of the rubber will bemixed in the rubber compound to be calendered on the textile material.The ratio of the two components of the resin is not critical andgenerally will be from 1 to 4 moles, ifiefcrably 1 to 2 moles of theresoreinol per mole of the iN-methylolamide. After building therubbercoated tex tile material into the finished article, e.g. a tire,the assembly is heated to vulcanize the rubber components thereof. Theadhesion of the textile material to the adjacent vulcanized rubber stockis greatly improved by means of the resin formed at the vulvanizingtemperatureby the reaction of the resoreinol and the N- methylolamideadjacent the interface of 'the textile material and the rubber of thelaminate.

The N-methylolamides that may be used are the N- ice methylolamides ofaliphatic monocarboxylic acids having 2 to 9 carbon atoms and theN-methylolcyclicimides of dicarboxylic acids. TheseN-methylolcarboxamido compounds are known and may be prepared in knownmanner by reacting equimoiar proportions of formaldehyde and theselected monocarboxylic acid amide or dicarboxylic acid cyclicimide.References: Chwala, Monatsh 78, 172- 3 (1948); Sachs, Berichte 31, 1231(1898); Tawney U.S. Patent No. 2,526,517. Examples of theN-methylolamides of monocarboxylic acids that may be used are N-methylolaoetamide, N-methylolbutyramide, N-methylolacrylamide,N-methylolmethacrylamide. Examples of the N-methylolcyclicimides ofdioarboxylic acids that may be used are N-methylolsuccinimide,N-methylolmaleimide, N-methylolitaconimide, N methylolcitraconimide, N-methylolphthalimide, N methylolhexahydrophthalimide, N-methyloll,2,3,G-tetrahydroph-thalimide, N-methylol- 3,6 endomethylene Atetrahydrophthalimide. These compounds all contain a methylolcarboxamidogrouping The rubber used in the present invention for making the rubberand fabric laminates for use in tire manufacture and for other purposesmay be natural (Hevea) rubber or conjugated diolefine polymer syntheticrubber or mixtures of any of them including their reclaims. Suchconjugated diolefine polymer synthetic rubbers are polmers ofbutadienes-l,3, e.g. butadiene-l,3, isoprene, 2,3-dimethylbutadiene-l,3,and mixtures thereof and polymers of mixtures of such butadienes-l,3with up to 50% of such mix-tures of compounds which contain a CH,= Cgroup and which are copolymerizable with butadienes-1,3, e.g. where atleast one of the disconnected valences is attached to an electronegativeradical, that is a radical which increases the polar character of themolecule, such as vinyl, phenyl, nitrile, carboxy radicals. Examples ofsuch conjugated diolefine polymer synthetic rubbers are polybutadiene,polyisoprene, butadiene-styrene copolymers (SBR) andbutadiene-acrylonitrile copolymers. The rubber will also containconventional compounding and vulcanizing ingredients such as carbonblack, antioxidants, sulfur, zinc oxide, accelerators, rubber processingor softening oils which may be added as such or may be present fromoil-extended rubbers. The textile material may be made of any of theconventional textiles used for reinforcing rubber, such as nativecellulose (e.g. cottons), 'egenerated cellulose (e.g. rayons), andsynthetic linear polyamides (e.g. nylons).

The following illustrates the invention. ferred to herein are by weight.

A rubber compound A was prepared by milling 1.25 parts of resoreinolinto a masterbatch of parts of natural rubber and 20 parts of carbonblack at about C. After cooling, the following ingredients were mixedinto the batch at about 70" C. in the following order: 10 parts of zincoxide, 2. parts f mm; acid, r part of accelerator SNS(N-tertiary-butyl-Z-benzothiazolesulfenamide), 1 part of antioxidant BLE(condensation product of acetone and diphenylamine), 1.25 parts of N-methylolacrylamide, and 3.5 parts of sulfur.

A rubber compound B was prepared in a similar man ner to compound Aexcept 1.60 parts of N-methylolmalzimide was added instead of theN-methylolacrylarm e.

A rubber compound C was prepared in a similar manner to compound Aexcept 2.20 parts of N-methylolphthalimide was added instead of theN-methylolacrylamide.

A control rubber compound D was prepared in a sim- All parts reilarmanner to compound A except the resorcinol and N-methylolacrylamide wereomitted.

The adhesion of the rubber compounds A to D to t re cords made of barerayon and nylon fibres was measured at 250 F. by the "H" adhesion testdescribed in Ind. Rub. World, vol. 114, page 213 (346), Study of the HTest for Evaluating the Adhesive Properties of Tire Cord in Natural andGR-S Rubbers, and in United States Department of Agriculture BulletinA1C-99 (1945), by Lyons, Nelson and Conrad. -In the "H" test, the cordunder test coated with the rubber compound under test is embedded in twoseparated standard rubber blocks and the assembly vulcanized. The poundsnecessary to pull the adhered cord free of one of the rubberblocks isthe "14 adhesion value. The higher the figure, the better the adhesionof the rubber coating to the cord. Test pieces for the rubber compoundsA to D were vulcanized for .30 minutes at 307 F. The results are shownin the following table:

Comparing the "H" adhesion values of compounds A, B and C with compoundD clearly shows the great improvement in adhesion of fibrous material torubber by the present invention.

In view of the many changes and modifications that may be made withoutdeparting from the principles underlying the invention, reference shouldbe made to the appended claims for an understanding of the scope of theprotection afforded the invention.

Having thus described my invention, what 1 claim and desire to protectby Letters Patent is:

1. 1n the method of adhering textile material to rubber by applying avulcanizable rubber coating to a textile material and heating theassembly to vulcanize the rubber, the step which comprises incorporatingin at least the portion of the assembly adjacent the interface of thetextile material and rubber coating before vulcanization resorcinol andan N-methylol carboxylic acid amide.

2. A method of adhering textile material to rubber which comprisesapplying to textile material a solid dry vulcanizable rubber compositioncontaining resorcinol and an N-methylol carboxylic acid amide, andheating the assembly to vulcanize the rubber and to firmly adhere thetextile material to the rubber composition.

3. A method of adhering textile material to rubber which comprisesapplying to a textile material a solid dry vulcanizable rubbercomposition comprising rubber selected from the group consisting ofnatural Hevea rubber and conjugated diolefine polymer synthetic rubberswhich are polymers of material selected from the group consisting ofbutadiene-l,3, isoprene, 2,3-dimethyl butadienc-l,3, and mixturesthereof, and mixtures of such butadienes-1,3 with up to 50% of themixtures of compounds which contain a CH,=C group and which arecopolymerizable with butadlenes-l,3, said rubber composition containingresorcinol and an N-methylolcarboxamido compound selccted from the groupconsisting of N-methylolamides of aliphatic monocarboxylic acid having 2to 9 carbon atoms and N-methylolcyclicimides of dicarboxylic acids andheating the assembly to vulcanizc the rubber and to firmly adhere thetextile material to the vulcanized rubber comconsisting of natural Hevearubber and conjugated di-.

olcfine polymer synthetic rubbers which are polymers of materialselected from the group consisting of butadicne-i,3, isoprene,2,3-dimethyl hutadiene-1,3, and mixtures thereof, and mixtures of suchbutadienes-Lii with up to 50% of the mixtures of compounds which containa CH ==C group and which are copolymcrizable with butadienes-l,3, saidrubber composition containing resurcinol and a compound selected fromthe group consisting of N-methylolamides of aliphatic monocarboxylicacids having 2 to 9 carbon atoms and N-rnethylolcyclicimides ofdicarboxylic acids, to a textile material selected from the groupconsisting of cotton, rayon and nylon to coat the same, and heating theassembly to vulcanize the rubber and to firmly adhere to textilematerial to the vulcanized rubber composition.

5. A method of adhering textile material to rubber which comprisesapplying a solid dry vu'lcanizable rubber composition comprising rubberselected from the group consisting of natural Hevea rubber andconjugated diolefine polymer synthetic rubbers which are polymers ofmaterial selected from the group consisting of butadiene- 1,3, isoprene,2,3-dimethyl butadiene-l,3, and mixtures thereof, and mixtures of suchbutadienes-LB with up to 50% of the mixtures of compounds which containa CH =C group and which are copolymerizable with -butadiencs-l,3, saidrubber composition containing resorcinol and N-methylolacrylamide, to atextile material selected from the group consisting of cotton, rayon andnylon to coat the same, and heating the assembly to vulcanize the rubberand to firmly adhere the textile material to the vulcanized rubbercomposition.

6. An assembly of textile material and a vulcanized rubber compositioncontaining an in situ formed resinous reaction product of resorcinol andan N-methylol car- 'boxylic acid amide.

7. An 'assembly' of textile material and a vulcanized rubber compositioncontaining an in situ formed resinous reaction product of resorcinol andan N-methylolcarboxamido compound selected from the group consisting ofN-methylolamides of aliphatic monocar-boxylic acids having 2 to 9 carbonatoms and N-methylolcyclicimides of dicarboxylic acids.

8. An assembly of textile material and a vulcanized rubber compositioncontaining an in situ formed reaction product of resorcinol and anNmethylolamide of an allphatic monocarboxylic acid having 2 to 9 carbonatoms.

9. An assembly of textile material and a vulcanized rubber compositioncontaining an in situ formed reac tion product of rcsorcinol and anN-methylolcyclicimide of a dicarboxylic acid.

10. An assembly of textile material and a vulcanized rubber compositioncontaining an in situ formed reaction product of resorcinol andN-mcthylolacrylamide.

11. A laminate of tire cord fabric and a vulcanized rubber tire carcassstock containing an in situ formed resinous reaction product ofresorcinol and an N-methylol earboxylic acid amide.

12. A laminate of tire cord fabric and a vulcanized rubber tire carcassstock containing an in situ formed resinous reaction product ofresorcinol and an N-metnylolcarboxamido compound selected from the groupconsisting of N-methylolamides of aliphatic monooarboxylic acids having2 to 9 carbon atoms and N-methylolcyclicimides of dicarboxylic acids.

13. A laminate of tire cord fabric and a vulcanized rubber tire carcassstock containing an in situ formed resinous reaction product ofresorcinol and an N-methylolamide of an aliphatic monocarboxylic acidhaving 2 to 9 carbon atoms.

14. A laminate of tire cord fabric and a vulcanized rubber tire carcassstock containing an in situ formed resinous reaction product ofresorcinol and an N-mcthyl0l cyclicimide of a dicanboxylic acid.

15. A laminate of tire cord fabric and a vulcanized rubber tire carcassstock containing an in situ formed resinous reaction product ofresoncinol and N-methylolaorylamide.

16. A rubber composition for adhering strongly to textile material whenvulcanized thereto comprising a vulcanizable rubber compositioncontaining resorcinol and an N-methylol carboxylic acid amide.

17. A solid dry rubber composition for adhering strongly to textilematerial when vulcanized thereto comprising a vulcanizable rubbercomposition containing resorcinol and an N-methylolcarboximido compoundselected from the group consisting of N-methylolamides of aliphaticmonocarboxylic acids having 2 to 9 carbon atoms andN-methylolcyclicimides of dicarboxylic acids.

18. A solid dry rubber composition for adhering strongly to textilematerial when vulcanized thereto comprising a vulcanizable rubbercomposition containing resorcinol and an N-methylolamide of an aliphaticmonocarboxylic acid having 2 to 9 carbon atoms.

19. A solid dry ru bber composition for adhering 5 strongly to textilematerial when vulcanized thereto comprising a vulcanizable rubbercomposition containing resorcinol and an N-methylolcyclicimide of adicarboxylic acid.

2 0. A solid dry rubber composition for adhering strongly to textilematerial when vulcanized thereto comprising a vulcanizable rubbercomposition containing resorcinol and N-methylolacrylamide.

No references cited.

4. A METHOD OF ADHERING TEXTILE MATERIAL TO RUBBER WHICH COMPRISESAPPLYING A SOLID DRY VULCANIZABLE RUBBER COMPOSITION COMPRISING RUBBERSELECTED FROM THE GROUP CONSISTING OF NATURAL HEVEA RUBBER ANDCONJUGATED DIOLEFINE POLYMER SYNTHETIC RUBBERS WHICH ARE POLYMERS OFMATERIAL SELECTED FROM THE GROUP CONSISTING OF BUTADIENE-1,3, ISOPRENE,2,3-DIMETHYL BUTADIENE-1,3, AND MIXTURES THEREOF, AND MIXTURES OF SUCHBUTADIENES-1,3, WITH UP TO 50% OF THE MIXTURES OF COMPOUNDS WHICHCONTAIN A CH2=C< GROUP AND WHICH ARE COPOLYMERIZABLE WITH BUTADIENES-1,3SAID RUBBER COMPOSITION CONTAINING RESORCINOL AND A COMPOUND SELECTEDFROM THE GROUP CONSISTING OF N-METHYLOLAMIDES OF ALIPHATICMONOCARBOXYLIC ACIDS HAVING 2 TO 9 CARBON ATOMS ANDN-METHYLOLCYCLICIMIDES OFF DICARBOXYLIC ACIDS, TO A TEXTILE MATERIALSELECTED FROM THE GROUP CONSISTING OF COTTON, RAYON AND NYLON TO COATTHE SAME, AND HEATING THE ASSEMBLY TO VULCANIZE THE RUBBER AND TO FIRMLYADHERE TO TEXTILE MATERIAL TO THE VULCANIZED RUBBER COMPOSITION.